1. Field of the Invention
The present invention relates to a color filter and a method for producing the same being most suitable for the fabrication of a color filter to be used in a liquid crystal display, solid-state image sensing device, or the like.
2. Description of the Related Art
A color filter is an essential component part of a liquid crystal display (LCD) and of solid-state image sensing devices (such as a CCD, CMOS, etc.)
Compared with a CRT, as a display device an LCD is more compact and is equivalent or superior in performance. Therefore, the LCD is gradually replacing the traditional CRT as the display member of television screens, personal computer screens, and other display devices. Recently the technological trend in LCDs has been away from conventional monitors that have a screen with a relatively small surface area, and toward TVs that require a large, high quality image.
In LCD color filter applications the size of the substrate is expanded for large-screen TV use, and to increase productivity when such a large substrate is used, a low energy-curable composition is desirable for forming the color pixels (i.e., color filters) for red (R), green (G), and blue (B), etc.
Furthermore, an LCD used in a TV requires higher image quality than that of a conventional monitor. This means it requires enhanced contrast and color purity. For enhanced contrast the particle size of the colorants (organic pigments, etc.) in the curable composition used for forming the color pixels (color filters) must be reduced (see, for example, Japanese Patent Application Laid-open No. 2006-30541). However, as the particle size has decreased, the amount of dispersant added to disperse the pigment has tended to increase. Moreover, for enhanced color purity the content of colorant (organic pigment, etc.) in the solids of the curable composition must be increased. However, as the colorant content has increased, the relative content of photopolymerization initiator and photopolymerizable monomer in the solids of the curable composition has tended to decrease.
On the one hand, thin film pattern forming has advanced in color filter applications for solid-state image sensing devices, and concurrently the pigment concentration in the curable resin compositions has also increased. In addition, the ratio of pigment dispersant in the curable resin compositions has tended to increase as the pigment particles have become finer. Therefore, the relative content of photopolymerization initiator and photopolymerizable monomer has decreased.
Thus, in color filter applications for both LCDs and solid-state image sensing devices, the content of photopolymerization initiator and photopolymerizable monomer, which are both necessary components for curing a curable composition, has become restricted, and the pigment concentration has also increased. As a result, adhesion between the pigment and the inorganic material forming the substrate is no longer sufficient, and forming a desired pattern has become markedly more difficult.
Concerning the above, techniques involving the introduction of a silane coupling agent to enhance adhesion to the inorganic substrate have been proposed (for example, Japanese Patent Application Laid-open No. H2-127602, Japanese Patent Publication No. 2874091, and Japanese Patent Application Laid-open No. H11-38226). In addition, technology involving the introduction of a primary or secondary amine type silane coupling agent has been proposed as a technique to prevent development residue in regions that are conventionally developed and removed (unexposed parts in a negative photoresist) (for example, see Japanese Patent Application Laid-open No. 2000-35670).